An energy-saving method for operating an oil pumping unit

Abstract

This invention discloses an energy-saving method for operating an oil pumping unit, comprising the following steps: S1, selecting a motor compatible with the oil pumping unit according to its model, including the motor type and rated active power; S2, determining the maximum stroke rate matching the oil pumping unit, and classifying the oil pumping unit based on the maximum stroke rate; S3, installing an oil pumping unit stroke adjustment device between the oil pumping unit and the motor, and determining the oil pumping unit stroke adjustment device; S4, obtaining the optimal diameter of the output shaft of the stroke adjustment device; S5, adjusting the balance of the oil pumping unit. This energy-saving method for operating an oil pumping unit achieves the goals of reducing the stroke rate of the oil pumping unit, improving the natural power factor of the motor, and achieving high-efficiency energy saving. Simultaneously, it avoids the problem of excessively low voltage and frequency leading to a decrease in the speed of the motor's cooling fan, resulting in poor coil heat dissipation and accelerated insulation aging, causing premature failure.

Description

Technical Field

[0001] This invention relates to the field of energy and water conservation technology in oilfields, and in particular to an energy-saving method for operating an oil pumping unit. Background Technology

[0002] According to the 2021 Energy Conservation Monitoring Bulletin of North China Oilfield Company, the system efficiency qualification rate was 79.26%, the motor power factor qualification rate was 49.48%, the pumping unit balance qualification rate was 51.28%, and the power consumption per ton of fluid per 100 meters was 1.527 kWh, with an overall compliance rate of only 21.61%. This indicates that the existing measures are ineffective and do not comprehensively consider standard assessment parameters. When the pumping unit system efficiency is below 22%, the unit power consumption of fluid production increases rapidly. In our plant, 59.2% of oil wells have an efficiency below 22%, indicating severely low system efficiency and increased unit power consumption of the pumping unit system. The natural power factor qualification rate of the motor was 34.45%, and the line loss qualification rate of the 6KV line was only 10%, indicating high power system losses.

[0003] Currently, the production rate of oil wells in the oilfield is generally low. To improve the efficiency of the pumping unit system and reduce line power consumption, the methods adopted are to reduce the stroke rate, such as frequency conversion measures of frequency converters and speed reduction measures of reduction gears. These measures can only reduce the stroke rate of the pumping unit, but this measure reduces the work done by the motor per unit time, that is, the load rate of the motor, causing the motor's natural power to decrease, thereby increasing the losses of low-voltage and high-voltage lines. At this time, due to the decrease in power factor, the measure taken is low-voltage capacitor compensation. However, the existing technology cannot achieve smooth reactive power compensation for a motor with an average input active power of 3KW, causing the capacitor to be in an over-compensated state for a long time, which aggravates the attenuation, shortens the life cycle of the capacitor, and results in large investment and poor effect.

[0004] Therefore, it is essential to combine reducing the number of strokes with improving the natural power factor of the motor to optimize the power system's normal power consumption and line losses.

[0005] The published patent CN 201410173596.5 provides a variable frequency energy-saving method for oil pumping units, which includes: Step 1: After starting the equipment, initialize the oil pumping unit control system and adjust the balance of the oil pumping unit; Step 2: Determine whether the oil pumping unit is in power frequency working mode or variable frequency working mode; if it is in power frequency working mode, maintain the oil pumping unit in power frequency working mode; if the oil pumping unit is in variable frequency working mode, determine whether the frequency converter is faulty; Step 3: If the frequency converter is faulty, adjust the oil pumping unit to power frequency working mode and maintain the oil pumping unit in power frequency working mode; if the frequency converter is not faulty, proceed to Step 4; Step 4: Determine whether the oil pumping unit is in automatic stroke adjustment mode or manual stroke adjustment mode; if... If the pumping unit is in manual stroke adjustment mode, the stroke rate of the pumping unit will be adjusted manually by the operator. If the pumping unit is in automatic stroke adjustment mode, proceed to step 5. Step 5: The pumping unit control system collects the pumping unit indicator diagram data, obtains the indicator diagram based on the collected data, and then analyzes the shape characteristics of the obtained indicator diagram to determine if there is a fault in the pumping unit. Step 6: If there is a fault in the pumping unit, the fault is handled. If there is no fault in the pumping unit, it is determined whether the pumping unit needs intermittent pumping control. If intermittent pumping control is required, the pumping unit control system will perform intermittent pumping control. If intermittent pumping control is not required, proceed to step 7. Step 7: The pumping unit control system will automatically adjust the stroke rate of the pumping unit.

[0006] The published patent CN201410854633.9 provides an energy-saving method for a walking beam pumping unit. This method includes the following steps: 1) Replacing a large walking beam pumping unit with a small walking beam pumping unit, connecting a well balancer to the pumping pump, and connecting the top of the well balancer to the donkey head suspension point; 2) Adding a crank balance block to the tail end of the crank, adjusting the weight of the crank balance block so that the torque generated by the average of the maximum and minimum loads at the donkey head suspension point on the walking beam support is equal to the torque generated by the crank balance block on the walking beam support; 3) A servo motor drives the ball screw to rotate, and the ball screw drives the sliding balance block to roll on the walking beam. The weight of the sliding balance block is adjusted to be half the difference between the maximum and minimum loads at the donkey head suspension point. The weight of the servo motor is incorporated into the weight of the crank balance block. The load sensor collects the load at the donkey head suspension point, and the position sensor collects the horizontal distance from the sliding balance block to the walking beam support. The load at the donkey head suspension point, the horizontal distance from the sliding balance block to the walking beam support, the weight of the sliding balance block, and the torque of the crank balance block on the walking beam support are input to the CPU controller. The CPU controller outputs a signal to the servo motor. After receiving the signal, the servo motor drives the sliding balance block to move to a position where the torques at both ends of the walking beam support are equal.

[0007] The published patent CN 201911028115.0 provides a method for dynamic adjustment and multi-level voltage regulation energy-saving control of oil pumping unit balance, which includes the following steps: Step 1: Using a dynamic adjustment balancing device, the balancing torque is adjusted in real time by controlling the DC motor to adjust the equivalent force arm (ADX) of the dynamic balancing weight, thereby achieving real-time control of dynamic balance and reducing the peak power of the oil pumping unit motor; Step 2: After the real-time control of dynamic balance is completed, before performing voltage regulation energy-saving control, the peak power and the duration of the heavy-load operation area are first identified based on the discrete data of the input power of the oil pumping unit during one cycle of operation; Step 3: ... Step 3: When performing multi-level voltage regulation control, to ensure the safe and stable operation of the system, based on the motor principle, the minimum voltage limit is calculated according to the peak power and the voltage regulation safety factor; the voltage regulation safety factor is obtained based on the duration of the heavy-load operation area; Step 4: A two-stage double-winding transformer combined with star-delta connection is used to achieve voltage regulation through delta-connection step-down, star-connection step-up, star-connection, and star-connection step-down control methods, and a voltage level matrix is ​​obtained after voltage regulation; Step 5: Select the voltage regulation level in the voltage level matrix that is greater than or equal to the minimum voltage limit, calculate the minimum motor loss, and use the voltage regulation level with the minimum motor loss as the final control voltage regulation level.

[0008] However, while the aforementioned technical solutions include software modules or modifications to the pumping unit structure to achieve energy savings, the programs are complex and costly, making them unsuitable for extensive upgrades to existing pumping units. Furthermore, monitoring via software modules introduces errors; changes in a specific parameter (the pumping unit's balance) can affect parameter adjustments, impacting subsequent judgments. Interference with intelligent monitoring can also render the frequency converter inoperable, preventing the reduction of pumping unit stroke rate. Therefore, there is an urgent need to design an energy-saving improvement scheme for pumping units that simultaneously addresses both stroke rate reduction and the improvement of the motor's natural power factor. Summary of the Invention

[0009] The purpose of this invention is to provide an energy-saving method for operating oil pumping units in existing power systems that solves the problems of small stroke adjustment range and low natural power factor of electric motors.

[0010] Therefore, the technical solution of the present invention is as follows:

[0011] An energy-saving method for operating an oil pumping unit includes the following steps:

[0012] S1. Select a motor compatible with the pumping unit based on its model; the motor type should be a four-pole permanent magnet motor; the rated active power P of the motor... e It should satisfy: P e ≤P r / β,P r β represents the average input active power of the electric motor originally used in the pumping unit, and β is the minimum load rate of the motor, which is 20%.

[0013] S2. Determine the maximum stroke rate that matches the pumping unit, and classify the pumping unit into stroke ranges based on the maximum stroke rate; wherein,

[0014] S201, According to the formula: T e =9550·P e / N, calculate the rated torque T of the motor's output shaft. e In the formula, P e Where N is the rated power of the motor, and N is the speed of the motor.

[0015] S202, According to the formula: N max =9550·P w / T d The maximum rotational speed N of the output shaft of the pumping unit's gearbox was calculated. max The result is rounded to one decimal place; in the formula, P w P is the output power of the output shaft of the pumping unit's gearbox. w =P e ×η1×η2, where η1 is the transmission efficiency of the stroke adjustment device, and η2 is the total transmission efficiency from the original motor to the output shaft of the pumping unit reducer; T d Output shaft torque of the pumping unit gearbox;

[0016] S203, The maximum speed N of the pumping unit gearbox output shaft calculated in step S202 is... max The maximum stroke n corresponding to the oil pumping unit max Then, based on the same stroke interval Δn, multiple stroke values ​​n are obtained in a progressively decreasing manner, including: n = n max -Δn, n=n max -2Δn, ..., n=n max -jΔn, where j is a positive integer, and the value n of each impulse should satisfy n≥1.5;

[0017] S204. Based on the strokes n corresponding to each gear obtained in step S203, according to the formula: N 转 =150·n, and the output speed N corresponding to each gear of the stroke adjustment device is calculated respectively. 转 ;

[0018] S3. Install a pumping unit stroke adjustment device between the pumping unit and the motor, and adjust the composition of the pumping unit stroke adjustment device according to the number of gears determined in step S2, including: 1) Determine the number of gear sets in the pumping unit stroke adjustment device to be M and the number of first shifting components to be M-1 according to the number of gears M determined in step S203; 2) Determine the output speed N corresponding to each gear as determined in step S204. 转The ratio between the output speeds corresponding to the stroke count from large to small is obtained, and then each gear set is configured with a driving gear and a driven gear with a suitable number of teeth so that the output shaft of the pumping unit stroke adjustment device can output multiple speeds that correspond to step S203.

[0019] S4. According to the formula: d min ≥C·(P e ·η1 / N 转min ) 1 / 3 The minimum diameter of the output shaft of the stroke adjustment device is calculated, where C is a constant with a value of 106; then d is calculated. min ×(1+5%) and take the integer value of the calculation result as the optimal diameter of the output shaft of the stroke adjustment device;

[0020] S5. According to the oil pumping unit balance adjustment formula: The distance Y that the balance block moves is calculated; where P 上 It is the average active power used during the upstroke of the pumping unit; P 下 M is the average active power used during the downstroke of the pumping unit; G is the mass of the counterweight moved on one side of the crank; P is the acceleration due to gravity; M is the average active power used during the downstroke of the pumping unit. 上 and P 下 The value is obtained by measuring with on-site instruments; when Y is negative, the balance block should move inward by a distance of Y; when Y is positive, the balance block should move outward by a distance of Y; if the calculated moving distance Y exceeds the movable distance of the balance block, the weight of the balance block is increased and the same calculation and moving operation is performed again.

[0021] Furthermore, in step S2, the stroke interval Δn is 0.8.

[0022] Furthermore, before step S5, a step of adding a compensation capacitor is included, specifically: adding a capacitor between the generator and the external power source; wherein the capacitance Q of the capacitor is... C According to the formula: The capacity of the compensation capacitor is calculated; where P is the average input active power of the new motor. To compensate for the previous power factor; The power factor after compensation is set to 0.85.

[0023] Compared with existing technologies, this energy-saving method for pumping unit operation achieves the goals of reducing pumping unit stroke rate, improving the motor's natural power factor, and achieving high energy efficiency through a series of improvements, including the sequential replacement of the pumping unit's matching motor, the addition of a pumping unit stroke rate adjustment device, the addition of a compensation capacitor, and balance adjustment. Field tests show that the method described in this application improves the natural power factor, system power factor, and balance, resulting in stable daily liquid production and reduced daily power consumption. In particular, the daily power consumption is reduced by 25.4% when the pumping unit is operating at low speed, significantly increasing daily output and effectively solving the problem of high energy consumption in the pumping unit system. Furthermore, it avoids the problem of reduced motor cooling fan speed due to excessively low voltage and frequency when adjusting stroke rate by adjusting voltage and frequency, which leads to poor coil cooling and accelerated insulation aging and premature failure. Therefore, this method has excellent application and promotion prospects. Attached Figure Description

[0024] Figure 1 This is a flowchart of the energy-saving method for operating an oil pumping unit according to the present invention;

[0025] Figure 2 This is a schematic diagram showing the motor efficiency zone division of the four-stage motor used in this invention;

[0026] Figure 3 This is a schematic diagram of the internal structure of the pumping unit stroke adjustment device added during the implementation of the energy-saving method for pumping unit operation in an embodiment of the present invention. Detailed Implementation

[0027] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but the following embodiments are by no means intended to limit the present invention.

[0028] like Figure 1 As shown, the specific implementation steps of this energy-saving method for operating the oil pumping unit are as follows:

[0029] S1. Select an energy-saving electric motor that is compatible with the oil pumping unit:

[0030] S101. Determine the type of motor:

[0031] To reduce internal power consumption, an energy-saving permanent magnet motor is used to solve rotor copper loss and improve the motor's load factor-power factor characteristics. The power factor does not change much with small load changes, keeping the low-voltage system operating within a reasonable line loss range. Specifically, a four-pole motor with two pairs of magnetic poles is used, with a speed of 1500 r / min.

[0032] S102. Determine the rated active power of the motor:

[0033] like Figure 2The diagram shows the efficiency zone division of a four-pole motor; Figure 2 In the diagram, the horizontal axis represents load rate, and the vertical axis represents motor efficiency. Based on the division of the economic operating zone (motor efficiency 87.12%), effective economic operating zone (motor efficiency 88%), and ideal economic operating zone (motor efficiency 88.44%) onto the horizontal and vertical axes, it can be seen that the motor efficiency reaches a relatively high value when the minimum load rate is 35% or higher. This reduces internal losses caused by insufficient work, thereby maximizing the motor's effectiveness. Therefore, to achieve an ideal motor efficiency of 87.12%–89.19%, the optimal maximum load rate is 35% or higher when the oil well is at its highest production, meeting the requirements for efficient motor operation. Simultaneously, according to enterprise standards, the minimum load rate of the motor should be ≥20%.

[0034] Based on the above analysis, the rated active power Pe of a motor is the ratio of the motor's average input active power to its load rate. Therefore, P is calculated based on this conversion relationship. e The result may not necessarily correspond to the rated active power of a commercially available four-pole permanent magnet motor. Therefore, the rated active power P of the motor... e It should satisfy: P e ≤P r / β,P r Let P be the average input active power of the original motor of the oil pumping unit, and β be the minimum load rate of the motor, which is taken as 20%; when the calculated rated active power P e If there is no commercially available four-pole permanent magnet motor that matches it, then select the motor model that is closest to the calculation result according to the above relationship;

[0035] S2. Determine the maximum stroke rate that matches the pumping unit, and classify the pumping unit into stroke rate classes based on the maximum stroke rate;

[0036] Specifically, the specific implementation of step S2 is as follows:

[0037] S201, According to the formula: T e =9550·P e / N, calculate the rated torque T of the motor's output shaft. e In the formula, P e Where N is the rated power of the motor, and N is the speed of the motor.

[0038] S202, According to the formula: N max =9550·P w / T c Calculate the maximum rotational speed N of the output shaft of the pumping unit's gearbox. max The result is rounded to one decimal place; in the formula, Pw The output power of the pumping unit's gearbox output shaft is calculated using the following formula: P w =P e ×η1×η2, where η1 is the transmission efficiency of the stroke adjustment device to be added between the motor and the pumping unit, and η2 is the total transmission efficiency from the original motor to the output shaft of the pumping unit reducer; T c The output shaft torque of the pumping unit's gearbox is obtained from on-site testing.

[0039] S203, The maximum speed N of the output shaft of the pumping unit gearbox calculated in step S202. max The maximum stroke n corresponding to the oil pumping unit max Then, based on the stroke interval Δn, multiple stroke values ​​n, which gradually decrease in value from large to small, are obtained in a sequentially decreasing manner, including: n = n max -Δn, n=n max -2Δn, ..., n=n max -jΔn, where j is a positive integer, and the value of each impulse n should satisfy n≥1.5; based on this, we obtain the maximum impulse n max As a high-speed gear, n = n max -jΔn represents multiple low-speed gears; where Δn is preferably 0.8.

[0040] In step S203, if n max -2Δn is greater than 1.5, while n max Since -3Δn is less than 1.5, three gears are determined through step S203: ① High speed gear, with corresponding strokes n = n max ② Medium speed gear, its corresponding strokes n = n max -Δn; ③ Low speed gear, the corresponding strokes n=n max -2Δn; and if n max -Δn is greater than 1.5, while n max Since -2Δn is less than 1.5, two gears are determined through step S203: ① High speed gear, with corresponding strokes n = n max ② Low speed gear, corresponding to stroke n = 1.5; that is, the pumping unit will have two corresponding speeds through the stroke adjustment device;

[0041] S204. Based on the strokes n corresponding to each gear obtained in step S203, according to the formula: N 转 =150·n, and the output speed N corresponding to each gear of the stroke adjustment device is calculated respectively. 转 ;

[0042] In practical use, the selection of the pulse rate adjustment device gear is determined based on the area of ​​the dynamometer card of the oil well. Generally speaking, when the dynamometer card S... 实际 For the area S of the indicator diagram标准 For over 80% of the time, select the high-speed setting of the stroke adjustment device, and operate when the indicator diagram S... 实际 For the area S of the indicator diagram 标准 When the speed is between 40% and 80%, the high speed setting of the stroke adjustment device should be changed to the medium speed setting. When the actual speed of the dynamometer S is less than 40% of the standard dynamometer area S, it should be changed to the low speed setting.

[0043] S3. Install a pumping unit stroke adjustment device between the pumping unit and the motor, and adjust the composition of the pumping unit stroke adjustment device according to the number of gears determined in step S2, so as to adjust the stroke of the pumping unit.

[0044] The pumping unit stroke adjustment device adopts the device for adjusting the pumping unit stroke provided by the published patent CN113983129A, and the pumping unit stroke adjustment device is used to adjust the pumping unit stroke.

[0045] Based on the number of gears M determined in step S203, the number of gear sets in the pumping unit stroke adjustment device is determined to be M, and the number of the first shifting components is M-1. The installation and engagement method between the gear sets and the first shifting components is the same as the installation and engagement method in the patent disclosure.

[0046] The output speed N corresponding to each gear determined in step S204 转 The ratios between the output speeds corresponding to the stroke count from large to small are obtained to determine the transmission ratios of each gear set from its input shaft to its output shaft on the pumping unit stroke adjustment device, so that the transmission ratios of each gear set can be adjusted to match the output speeds corresponding to the stroke count from large to small.

[0047] Furthermore, based on the transmission ratio of each gear set from its input shaft to its output shaft on the pumping unit stroke adjustment device, driving gears and driven gears with appropriate number of teeth are selected for each gear set to meet the above speed adjustment requirements, that is, the output shaft of the pumping unit stroke adjustment device can output multiple speeds that correspond to step S203.

[0048] S4. Determine the optimal output shaft radius of the stroke adjustment device to increase the output shaft torque;

[0049] According to the formula: d min ≥C·(P e ·η1 / N 转min ) 1 / 3 The minimum diameter of the output shaft of the stroke adjustment device is calculated; where C is a constant with a value of 106; then d is calculated. min ×(1+5%) and take the integer value of the calculation result as the optimal diameter of the output shaft of the stroke adjustment device;

[0050] S5. Add a capacitor to enable the oil pumping unit to use a low-voltage electric system for reactive power compensation;

[0051] According to the formula: The capacity of the compensation capacitor is calculated; where P is the average input active power of the new motor, which is obtained through on-site measurement. The power factor before compensation is obtained through on-site measurement; To compensate for the power factor, according to national standards, its value is ≥0.85;

[0052] When in use, the capacitor is connected between the motor and the external power supply to prevent the capacitor from being overcompensated and prematurely degraded, and at the same time reduce line loss.

[0053] S6. Adjust the balance of the pumping unit to reduce redundant power consumption caused by crank imbalance;

[0054] Due to the adjustments made in steps S1 to S5 above, the balance of the pumping unit will inevitably be affected and changed. Therefore, the balance of the pumping unit needs to be adjusted again; specifically,

[0055] According to the oil pumping unit balance adjustment formula: The distance Y that the balance block moves is calculated; where P 上 It is the average active power used during the upstroke of the pumping unit; P 下 M is the average active power used during the downstroke of the pumping unit; G is the mass of the counterweight moved on one side of the crank; P is the acceleration due to gravity; M is the average active power used during the downstroke of the pumping unit. 上 and P 下 Measured by on-site instruments;

[0056] Calculations show that when Y is negative, the balance block should move inward by a distance of Y; when Y is positive, the balance block should move outward by a distance of Y; if the calculated moving distance Y exceeds the movable distance of the balance block, the weight of the balance block should be increased before performing the same calculation and moving operation.

[0057] Taking the energy-saving renovation of an oil pumping unit at Quan 63-26 as an example, this application further describes the energy-saving improvement method.

[0058] The pumping unit at this location is model CYJY14-5.5-73HF. Before the modification, the pumping unit used a Y280M-8 motor (8-pole motor, 45KW), with an average liquid production of 2 tons and an average input power of 5.73KW. The problem with the pumping unit during operation was that the motor load rate was only 13%, resulting in a natural power factor of only 0.13, which did not meet the company standard requirement of 0.4. The balance was only 78%. After balancing, it met the company standard requirement of 80% to 120% balance, saving 4 kWh of electricity per day. However, the natural power factor of the motor and the power factor of the low-voltage system were not improved.

[0059] The maximum torque of the original pumping unit motor is: T d =9550×55÷740=709N·m; Rated torque of the pumping unit is 73KN.m, and the maximum output speed of the original pumping unit gearbox is N. max =4r / min, and then we can calculate the efficiency of the original transmission system η = 73000×4÷9550÷55 = 0.56; that is, when the transmission efficiency reaches 0.56, it can meet the rated torque requirement of the pumping unit. Therefore, by increasing the transmission efficiency and reducing the maximum output speed of the pumping unit gearbox, the motor capacity can be reduced, the output can be reduced, and the torque required by the pumping unit can also be reduced. Generally, 53KN.m can rotate a 14-type pumping unit.

[0060] Based on this situation, the oil pumping unit is improved in the following order:

[0061] S1. Select an energy-efficient electric motor compatible with the oil pumping unit; specifically,

[0062] The energy-saving generator uses a YGT180M-4 motor, which is a four-pole permanent magnet motor with a speed of 1500 rpm;

[0063] In addition, based on the average input active power P of the original motor of the oil pumping unit r Given the minimum load rate of the motor (20%), the rated active power P of the new motor is calculated. e It should satisfy: P e ≤P r / β, i.e., P e ≤

[0064] 5.73 / 0.2 = 28.65KW; Based on this calculation result, a generator with a rated power of 22KW was finally selected; The load rate corresponding to this generator was calculated to be 26%, which meets the requirements;

[0065] S2. Determine the maximum stroke rate matched with the pumping unit, and classify the pumping unit into stroke ranges based on the maximum stroke rate; specifically,

[0066] S201, According to the formula: T e =9550·P e / N=9550×22÷1500=140.07N·m, the rated torque T of the motor's output shaft is calculated. e It is 140.07 N·m;

[0067] S202. Based on the pre-installed stroke adjustment device transmission efficiency η1 being 0.97, and the total transmission efficiency η2 from the original motor to the output shaft of the pumping unit reducer being 0.96, the power P of the output shaft of the pumping unit reducer of the stroke adjustment device is calculated. w =P e ×η1×η2=22×0.97×0.96=20.49KW; The maximum speed N of the output shaft of the pumping unit's gearbox can then be calculated. max =9550·P w / T c =20.49×9550÷53000=3.69r / min; N max The result, rounded to one decimal place, is 3.7.

[0068] S203, The maximum speed N of the output shaft of the pumping unit gearbox calculated in step S202. max The maximum stroke n corresponding to the oil pumping unit max =3.7, and then based on the stroke interval Δn = 0.8, the maximum output speed of the pumping unit gearbox is 3.7 r / min, thus determining the three speeds of the pumping unit, including: ① high speed, with a corresponding stroke of 3.7; ② medium speed, with a corresponding stroke of 2.9; ③ low speed, with a corresponding stroke of 2.1.

[0069] S204. According to the formula: N 转 =150·n, and the output speed N corresponding to each gear of the stroke adjustment device is calculated respectively. 转 Specifically, ① high speed gear has a stroke of 3.7 and a speed of 555 r / min; ② medium speed gear has a stroke of 2.9 and a speed of 435 r / min; ③ low speed gear has a stroke of 2.1 and a speed of 315 r / min.

[0070] S3, such as Figure 3 As shown, a pumping unit stroke adjustment device is installed between the pumping unit and the motor. The composition of the pumping unit stroke adjustment device is adjusted according to the number of gears determined in step S2 to meet the requirements for adjusting the stroke of the pumping unit.

[0071] 1) A pumping unit stroke adjustment device is added between the motor and the pumping unit. Specifically, the device for adjusting the pumping unit stroke provided by the published patent CN113983129A is adopted. During installation, the output shaft of the motor is connected to the input shaft of the pumping unit stroke adjustment device, the output shaft of the pumping unit stroke adjustment device is connected to its pulley, the pulley is connected to the large pulley of the pumping unit through a belt, the large pulley is connected to the input shaft of the pumping unit gearbox through a shaft, and the output shaft of the gearbox is connected to the crank of the pumping unit.

[0072] 2) Based on the number of gears determined in step S203, which is 3, the number of gear sets C in the pumping unit stroke adjustment device is determined to be 3, and the number of first shift components A is 2. The installation and engagement method between the gear sets and the first shift components is the same as the installation and engagement method in the patent disclosure.

[0073] 3) The output speed N corresponding to each gear determined in step S204 转 The ratios between the output speeds corresponding to the decreasing stroke rate are obtained to determine the transmission ratios of each gear set from its input shaft to its output shaft on the pumping unit stroke rate adjustment device. Then, driving and driven gears with appropriate tooth counts are selected for each gear set to meet the aforementioned speed adjustment requirements, i.e., the output shaft of the pumping unit stroke rate adjustment device can output multiple speed levels consistent with step S203. The function of the transition gear set B is to achieve zero-level speed change for the coarse adjustment device, that is, to first reduce the motor's speed from 1500 r / min to... 750r / min, gear set C1 functions as a first-stage speed change, that is, reducing 750r / min to 550r / min, gear set C2 functions as a second-stage speed change, that is, reducing 750r / min to 435r / min, and gear set C3 functions as a third-stage speed change, reducing 750r / min to 315r / min, thereby enabling the output shaft of the pumping unit stroke adjustment device to adjustably output speeds of 555r / min, 435r / min, and 315r / min respectively;

[0074] S4. Determine the optimal output shaft radius of the stroke adjustment device:

[0075] According to the formula: T z =9550·P e ·η1 / N 转min =9550×22×0.97÷315=647N.m, the maximum torque T of the output shaft of the stroke adjustment device is calculated. z It is 647 N·m;

[0076] According to the formula: T d =9550·P' / N' 转 =9550×55÷740=709N·m, the maximum torque T of the original motor is calculated.d The value is 709 N·m; correspondingly, the rotational force F = T is calculated. d / (D / 2)=709÷0.085÷2=4.17KN;

[0077] According to the formula: d min =C·(P e ·η1 / N 转min ) 1 / 3 =106·(22·0.97 / 315) 1 / 3 =43.21mm, take the diameter of the output shaft of the stroke adjustment device as 45mm;

[0078] Correspondingly, the rotational force F = T is calculated. d / (D / 2)=647÷0.045÷2=7.18KN, which increases the rotational force at the same point compared to the original system;

[0079] S5. A capacitor is added between the generator and the external power supply to enable the pumping unit to achieve reactive power compensation using a low-voltage electrical system; the calculated capacity of the compensation capacitor is as follows:

[0080] S6. Adjust the balance of the pumping unit again, according to the pumping unit balance adjustment formula: The calculation showed that the distance Y of the balance weight movement exceeded the movement range, so two more balance weights were added, each weighing 1.3 tons, or 12.74 kN, and moved to the end of the crank, achieving a balance of 88%.

[0081] The energy-saving parameters before and after the improvement are shown in Table 1 below. The power consumption measurement location before installation is the distribution cabinet inlet, and the power consumption measurement location after installation is the distribution cabinet outlet.

[0082] Table 1:

[0083]

[0084] As can be seen from the test results in Table 1, after the configuration improvement of the pumping unit using the scheme of this application, the natural power factor, system power factor, and balance have all been improved. Not only has energy saving been improved, but the daily liquid production during the pumping process has also stabilized at 2 tons, instead of the original 1-3 tons. In particular, after the scheme improvement, the daily power consumption of the pumping unit in the low-speed mode is 53.959 kWh, which saves 25.4% of electricity, and the daily power saving has been greatly improved. It can also be inferred from the power factor that the line loss has been reduced.

Claims

1. A method for energy-saving operation of an oil pumping unit, characterized in that, The steps are as follows: S1. Select a motor compatible with the pumping unit based on its model; the motor type should be a four-pole permanent magnet motor; the rated active power P of the motor... e It should satisfy: P e ≤P r / β,P r β represents the average input active power of the electric motor originally used in the pumping unit, and β is the minimum load rate of the motor, which is taken as 20%. S2. Determine the maximum stroke rate that matches the pumping unit, and classify the pumping unit into stroke ranges based on the maximum stroke rate; wherein, S201, According to the formula: T e =9550·P e / N, calculate the rated torque T of the motor's output shaft. e In the formula, P e Where N is the rated power of the motor, and N is the speed of the motor. S202, According to the formula: N max =9550·P w / T d The maximum rotational speed N of the output shaft of the pumping unit's gearbox was calculated. max The result is rounded to one decimal place; in the formula, P w P is the output power of the output shaft of the pumping unit's gearbox. w = P e ×η1×η2, where η1 is the transmission efficiency of the stroke adjustment device, and η2 is the total transmission efficiency from the original motor to the output shaft of the pumping unit reducer; T d Output shaft torque of the pumping unit gearbox; S203, The maximum speed N of the gearbox output shaft calculated in step S202 is... max The maximum stroke n corresponding to the oil pumping unit max Then, based on the same stroke interval Δn, multiple stroke values ​​n are obtained in a progressively decreasing manner, including: n=n max -△n, n=n max -2△n,…,n=n max -j△n, where j is a positive integer, and the value n of each impulse should satisfy n≥1.5; If n max -2Δn is greater than 1.5, while n max Since -3Δn is less than 1.5, three gears are determined through step S203: ① High speed gear, with corresponding strokes n=n max ② Medium speed gear, its corresponding strokes n=n max -△n; ③ Low speed gear, the corresponding strokes n=n max -2△n; if n max -△n is greater than 1.5, while n max If -2Δn is less than 1.5, then two gears are determined through step S203: ① High speed gear, with corresponding strokes n=n max ② Low speed gear, corresponding to stroke n=1.5; S204. Based on the strokes n corresponding to each gear obtained in step S203, according to the formula: N 转 =150·n, and the output speed N corresponding to each gear of the stroke adjustment device is calculated respectively. 转 ; S3. Install a pumping unit stroke adjustment device between the pumping unit and the motor, and adjust the composition of the pumping unit stroke adjustment device according to the number of gears determined in step S2, including: 1) Determine the number of gear sets in the pumping unit stroke adjustment device to be M, and the number of first shifting components to be M-1, according to the number of gears M determined in step S203; 2) Determine the output speed N corresponding to each gear as determined in step S204. 转 The ratio between the output speeds corresponding to the stroke count from large to small is obtained, and then each gear set is configured with a driving gear and a driven gear with a suitable number of teeth so that the output shaft of the pumping unit stroke adjustment device can output multiple speeds that correspond to step S203. S4. According to the formula: d min ≥C·(P e ·η1 / N 转min ) 1 / 3 The minimum diameter of the output shaft of the stroke adjustment device is calculated, where C is a constant with a value of 106; then d is calculated. min ×(1+5%) and take the integer value of the calculation result as the optimal diameter of the output shaft of the stroke adjustment device; S5. According to the oil pumping unit balance adjustment formula: The distance Y that the balance block moved was calculated; where, It is the average active power used during the upstroke of the oil pumping unit; is the average active power used during the downstroke of the pumping unit; m is the mass of the counterweight moved on one side of the crank; G is the acceleration due to gravity. and The value is obtained by measuring with on-site instruments; when Y is negative, the balance block should move inward by a distance of Y; when Y is positive, the balance block should move outward by a distance of Y; if the calculated moving distance Y exceeds the movable distance of the balance block, the weight of the balance block is increased and the same calculation and moving operation is performed again.

2. The energy-saving method for operating an oil pumping unit according to claim 1, characterized in that, In step S2, the stroke interval Δn is 0.

8.

3. The energy-saving method for operating an oil pumping unit according to claim 1, characterized in that, Before step S5, there is a step of adding a compensation capacitor, specifically: adding a capacitor between the generator and the external power source; wherein, the capacitance of the capacitor is... According to the formula: The capacity of the compensation capacitor is calculated; where P is the average input active power of the new motor. To compensate for the previous power factor; The power factor after compensation should satisfy the following values: ≥0.85.

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